The invention relates to a disk surface inspection apparatus capable of adjusting the sensitivity of an inspection optical system to a defect as a target of inspection and reducing the instrumental error between apparatuses of the optical system, an inspection system thereof, and an inspection method thereof.
Disks formed of glass, silicon wafer, etc. are used as materials for information recording media or semiconductors. Since the properties of products are deteriorated, when defects are present on the surface of the materials, inspection is conducted by a disk surface inspection apparatus. The disk surface inspection apparatus detects defects present on the disk surface. The defects include various kinds of defects, for example, dusts (particles) attached to the surface, stains, scratches caused by obstacles, fine concave portions (pits) and convex portions (bumps) or moderately inclined convex portions (bumps) or concave portions (dimples), deformation at disk ends formed by collision upon handling of disks (handling damages), and polishing traces on the disk surface (glides). As an effective detection method for such various types of defects, it has been used a method of detecting defects by irradiating a laser beam to a disk surface, and receiving optical feature, that is, reflection light or scattered light of the laser beam detected differently depending on the shape and the size of each of the defects respectively by a disk surface detection apparatus as described in JP-A No. 2001-66263.